Just an update from Sofia Airport.
Following flight cancelled into London BD7662
Flight FB495 due to leave Sofia 0745 now expected to leave for London 12.20. F.V.
I.L.S. stands for Instrument Landing System. Its a sysytem that most airfields have that helps aircraft land in adverse weather, eg fog and heavy rain.
I don't know if Plovdiv have it or if its just unserviceable.